// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_EVENTS_KEYCODES_DOM4_KEYCODE_CONVERTER_H_
#define UI_EVENTS_KEYCODES_DOM4_KEYCODE_CONVERTER_H_

#include <stddef.h>
#include <stdint.h>
#include <string>

#include "base/macros.h"
#include "ui/events/keycodes/dom/dom_key.h"

// For reference, the W3C UI Event spec is located at:
// http://www.w3.org/TR/uievents/

namespace ui {

enum class DomCode;

enum class DomKeyLocation { STANDARD,
    LEFT,
    RIGHT,
    NUMPAD };

// This structure is used to define the keycode mapping table.
// It is defined here because the unittests need access to it.
typedef struct {
    // USB keycode:
    //  Upper 16-bits: USB Usage Page.
    //  Lower 16-bits: USB Usage Id: Assigned ID within this usage page.
    uint32_t usb_keycode;

    // Contains one of the following:
    //  On Linux: XKB scancode
    //  On Windows: Windows OEM scancode
    //  On Mac: Mac keycode
    int native_keycode;

    // The UIEvents (aka: DOM4Events) |code| value as defined in:
    // http://www.w3.org/TR/DOM-Level-3-Events-code/
    const char* code;
} KeycodeMapEntry;

// A class to convert between the current platform's native keycode (scancode)
// and platform-neutral |code| values (as defined in the W3C UI Events
// spec (http://www.w3.org/TR/uievents/).
class KeycodeConverter {
public:
    // Return the value that identifies an invalid native keycode.
    static int InvalidNativeKeycode();

    // Convert a native (Mac/Win/Linux) keycode into a DomCode.
    static DomCode NativeKeycodeToDomCode(int native_keycode);

    // Convert a DomCode into a native keycode.
    static int DomCodeToNativeKeycode(DomCode code);

    // Convert a UI Events |code| string value into a DomCode.
    static DomCode CodeStringToDomCode(const std::string& code);

    // Convert a DomCode into a UI Events |code| string value.
    static const char* DomCodeToCodeString(DomCode dom_code);

    // Return the DomKeyLocation of a DomCode. The DomKeyLocation distinguishes
    // keys with the same meaning, and therefore the same DomKey or non-located
    // KeyboardCode (VKEY), and corresponds to the DOM UI Events
    // |KeyboardEvent.location|.
    static DomKeyLocation DomCodeToLocation(DomCode dom_code);

    // Convert a UI Events |key| string value into a DomKey.
    // Accepts a character string containing either
    // - a key name from http://www.w3.org/TR/DOM-Level-3-Events-key/, or
    // - a single Unicode character (represented in UTF-8).
    // Returns DomKey::NONE for other inputs, including |nullptr|.
    static DomKey KeyStringToDomKey(const std::string& key);

    // Convert a DomKey into a UI Events |key| string value.
    // For an invalid DomKey, returns an empty string.
    static std::string DomKeyToKeyString(DomKey dom_key);

    // Returns true if the DomKey is a modifier.
    static bool IsDomKeyForModifier(DomKey dom_key);

    // The following methods relate to USB keycodes.
    // Note that USB keycodes are not part of any web standard.
    // Please don't use USB keycodes in new code.

    // Return the value that identifies an invalid USB keycode.
    static uint32_t InvalidUsbKeycode();

    // Convert a USB keycode into an equivalent platform native keycode.
    static int UsbKeycodeToNativeKeycode(uint32_t usb_keycode);

    // Convert a platform native keycode into an equivalent USB keycode.
    static uint32_t NativeKeycodeToUsbKeycode(int native_keycode);

    // Convert a USB keycode into a DomCode.
    static DomCode UsbKeycodeToDomCode(uint32_t usb_keycode);

    // Convert a DomCode into a USB keycode.
    static uint32_t DomCodeToUsbKeycode(DomCode dom_code);

    // Convert a DOM3 Event |code| string into a USB keycode value.
    static uint32_t CodeToUsbKeycode(const std::string& code);

    // Static methods to support testing.
    static size_t NumKeycodeMapEntriesForTest();
    static const KeycodeMapEntry* GetKeycodeMapForTest();
    static const char* DomKeyStringForTest(size_t index);

private:
    DISALLOW_COPY_AND_ASSIGN(KeycodeConverter);
};

} // namespace ui

#endif // UI_EVENTS_KEYCODES_DOM4_KEYCODE_CONVERTER_H_
